1. Field of the Invention
The present invention relates generally to a contact type photoelectric converter device which is applicable to a facsimile transmitter, a character reader and the like. More particularly, the present invention concerns a contact type photoelectric converter device in which a light transmitting section for transmitting therethrough light emitted from a light source is juxtaposed in the vicinity of a row of separated photoconductive film, thereby providing a uniform illumination of an original and a high utilization efficiency of light.
2. Description of the Prior Art
Heretofore, a one-dimensional array of silicon photodiodes has been commonly used for a photoelectric converting section of a facsimile transmitter, a character reader or the like. Since a restriction is imposed on the length of the one-dimensional array, an image of an original to be read is focused on the silicon photodiode array in a reduced scale with the aid of a lens system. This arrangement suffers various drawbacks. For example, relatively large space is occupied by the optical system. Positional adjustment of lens are after required. Degraded resolution as well as insufficiency of light quantity will occur at a peripheral portion of the lens. As an attempt to eliminate these shortcomings, there has been recently proposed a contact type photoelectric converter device which is capable of reading information without using the lens system.
A typical example of the hitherto known contact type photoelectric converter device is shown in a transversal sectional view in FIG. 1 and in a perspective view in FIG. 2. Description will be made below on a structure of this photoelectric converter. On a light transmissive substrate 1 are formed light intercepting or shielding films 2, opaque stripe-like electrodes 3, photoconductive films 4 and a common overlying light transmissive electrode 5, thereby providing a one-dimensional array of photodiodes. A semiconductor element 6 for driving the photoelectric converter device is mounted on the light transmissive substrate 1 and is electrically connected to the strip-like electrodes 3 of the one-dimensional photodiode array. Subsequently, a light transmissive protection film 7 is formed over the one-dimensional photodiode array. A light source 8 is disposed on the substrate side of the thus constructed photoelectric converter device, while a sheet feeding roller 9 is disposed so as to be in contact with the protection film 7 of the one-dimensional photodiode array. An original 10 is fed between the protection film 7 and the feed roller 9. With the structure of such photoelectric converter device, the original 10 is illuminated with those light rays from the light source 8 which have passed through gaps provided between the opaque stripe-like electrodes 3, wherein light components scattered on the surface of the original 10 impinge on the photoconductive films 4, as can be seen from FIG. 3 which shows the photoelectric converter device in a longitudinal sectional view. Accordingly, in order to reduce shadows of the opaque strip-like electrodes 3 projected onto the original for accomplishing a uniform illumination of the original, it is necessary to widen gaps between the adjacent opaque stripe-like electrodes 3, which however means that the pitch l of the photoconductive films 4, that is, the resolution of reading is restricted. Further, with the structure of the photoelectric converter, those light components resulting from reflection of incident light rays impinging onto the original in perpendicular thereto will follow the return path toward the light source, whereby light components scattered on the original will impinge on the photoconductive film 4, involving poor utilization of light.